Telegraph exchange system



May 16, 1933. Q 3 LANE 1,909,838

TELEGRAPH EXCHANGE SYSTEM Filed Dec. 15, 1931 CENTRAL I 26 32 o R 6 INVENTOR f C. C LANE ATTORNEY Patented i 16,

UNITED" STATES PATENT OFFICE CUI'HBEBT GIANE, 01' LITTLE NECK, NEW YORK, ASSIGNOB T0 in! 'I'iI-BPKON'E LABORATORIES, mconrom'ra'n, 0! NEW YORK, 11'. Y., A CORPORATION 01' NEW YORK ZXCIIANGE SYSTEM Application fled December-.16, 19 81. Serial llo. 581,181.

I This invention relates to the subscribers station circuit for a printing telegraph exchange system and its object is to provide means for automatically repeating back to a callin subscriber the code number correspondmg to the station subscriber is connected. 4

A printing telegraph exchange system usually comprises a group of subscribers printer stations and one or more switchboard or central oflices for interconnecting the subscribers for communication purposes. Means may be provided at the switchboard for start ing the motors at a called subscribers station circuit for conditioning the printer set thereat to receive a message whenever the called station is unattended. The Locke-Kinkead copending application Serial No. 459,684, filed June 7, 1930 discloses a system of this type. It is often desirable in such systems to bring to the attention of the calling subscriber the code number of the unattended station to which he is connected before starting to transmit a message. Such an arran ement will prove a check on the central 0 cc operatorand will acquaint the calling party with the fact that he iscommunicating with y the correct part Broadly, this invention comprises means to transmit an answer-back signal to the calling subscriber. In accordance with this invention a shaft is connected to the keyboard of the subscribers printer set, transverse of the key levers, for engaging a group of the key levers in a predetermined order upon rotation of the shaft in order to repeat back to a calling subscriber the code numbercorresponding to the called station circuit. Theperiphfir of the shaft is drilled with numerous desired'key lever at any desired position of e shaft as it revolves. This shaft is arranged to'engage a driving member and to revolve one complete revolution. u n the actuation of the unattended start re ay in the subscribersstation circuit. Upon the completion of one revolution the driven member automatically disconnects itself.

A feature of the invention resides in the to which the calling es in such manner that studs ma be in serted in the holes to engage an Fig.- 1- illustrates a fragmentary lan view I of a telegraph-typewriter set in w ich only the essential parts necessary for a clear un derstanding of the invention are shown;

Fig. 2 is an elevation view of the typewriter set taken. at the right side of Fig. 1; an Fig. 3 is a schematic circuit arrangement of the essential eleme ts necessary to operate the telegraph-typewriter set of a called subscribers station when it is desired to transmit the code number of such station to a calling subscribers station.

Similar characters of reference designate similar parts throughout the several views.

As it is understood by those familiar with the art, keyboard-operated printing telegraph outfits are of at least two distinct kinds, one in which the character writing keys operate a mechanism for perforating a tu which is then fed through a transmitting d: vice for sending over the line impulses of difi'erent combinations corres nding to the grou s of letters or groups of gures, or both, whic the operated keys represent, in which the operated keys actuate the transmitting device directly for transmitting the signal combmations over the line. Either kind may be adapted for use in illustrating the resent in-' 150 they rest on rollers stop arm 14. The selector bars are respectively arranged in enga able relationwith five locking latches 15 so that when a key is depressed to move one or more selector bars endwise in 5 either direction, the locking latches respectively associated with the operated selector bars, will latch or unlatch, depending on the position of the selector bars at the time, one or more contact levers 16. Respectively arm ranged in engageable relation with the five contact levers are five contact cams 17. The contact cams are fixedly mounted on a rotatable shaft'18 which members 19 and 19' printer motor 21. The five contact levers 16 are respectively arranged to open and close five pairs of transmitting contacts in various combinations for transmitting over a line circuit extending to a distant station, a five-unit 20 code of .impulses representing each character of a message. One contact of each transmittin pair forms an integral part of bus-bar 22 an the other contact of each air forms an integral part of bus-bar 23, bot bus-bars being connected in series with the line circuit. The sending unit is of the type wherein the motor is driven to run at approximately a constant speed. When a character is sent, the motor, acting through gearing and the clutch, rotates the keyboard sending cams which successively engage the unlatched contact levers for operating the transmitting contacts to form t e combination of the particular character. In the stopped position the clutch is disengaged by the clutch stop arm 24 and whenever a key is depressed this arm is moved out-of engagement with its associated notch in the clutch member 19,

allowing the two clutch members 19 and 19' 4 to engage under the tension of coil spring 19" 11nd rotate the camshaft through one revoution.

Beneath the key levers are the five trans-.

verse selector bars and a universal bar, (the t5 latter is not shown but its use is well knownin the art) extending across the 'width of the keyboard. The selector bars are provided with saw-tooth sha d notches according to the requirements 0 the signaling code, and so that they move endwise easily in response to a depression of a key. When a key is depressed, it strikes theslantmg sides of the notches and moves, either to the right or to the left, one or more selector bars, depending on the key selected, to

determine whether the impulses corresponding to the bars are to be opened or closed circult impulses. The universal bar (not shown), which is connected to the clutch 24 controlling the starting and the stopping ofthe sending cams 17, is pivqted at its two ends in such a way that the depres- 'sionof any key l mtwes it dwnward to actuate the stop arm through the trip-ofi' pawl 66 25 and intermediate pawl 26.

is driven through clutch. by shaft 20 geared to the ent invention may This allows the transverse clutch teeth to engage, causing the sending cams 17 to lector bar engages a vertical lever or locking latch 15 atits right-hand extremity and positions it to correspond to the signal impulse to be transmitted. Each locking latch controls the motion of a contact lever 16 by either allowing the contact lever to close its-associated contact, or restrictingthe motion of the contact lever to hold when the. cam revolves. Each cam is provided with an indent in its periphery and these cams are so positioned on shaft 22 that the indents come into engageable relation with their respectively associated contact levers in a successive order through the rotation of the cam shaft through one revolution. This arrangement of the indents provides for transmitting the five impulses of a signal in a successive order. A sixth contactlever 27 controls the starting and stopping impulses. At the end of revolution of the cam, the stop arm 24 controlled b the universal bar in enters its notch on t e driven sleeve 19' o the clutch and prevents the cam from rotating further until another key is depressed.

A'locking bail 28 which engages the upper ends of the locking latches 15 at the beginning of each revolution prevents any chan e in the selection set up, until the revolution as been completed and the impulse of a si al have been transmitted. The bail is raised blga cam 29 near the end of, each revolution. is

the contact open,

make one revolution. Each sepress another key until the impulses for the previous signal or character have been sent out over the line.

The sending unit just described is well known in the art and requires no further explanation. The purpose of illustratin ithere 1S merely to show how the device of t e presbe applied. It is understood, however, that the present invention is not limited in scope to the arrangement shown herein. v The inventio herein resides essentially in the use of a rotatable shaft 30 mounted directly over the key levers 13 and provided with 'arallel rows of tapped holes extending comp etely around its periphery, each row being in alignment with a key lever. The number of holes in a row depend on the number of signals to be transmitted in order to complete the code number of a called station. The shaft is so positioned above the key levers that should a stud be inserted in any hole and the shaft rotated, the top of the stud would, upon reaching a key lever to an operated position. One stud is provided for each si al of the code num ber of the station at which the keyboard is located and the studs are so positioned, with respect to eachother, on shaft 30 that their angular distancesapa'rtare equal and their distances apart vary in accord theunderside, depress studs are equal.

ance with the locations of the keys which they are designed to operate. In other words, the

studs are positioned to form a somewhat spiral alignment around shaft 30 in which the sectorial angles of the spiral formed b the makes one complete revolution the studsengage their respectivel associated key levers successively and there y transmit to the lines 19 m their proper order the signal combinations re resenting the characters of the ofllce cod haft 30 IS driven rimarily from the main driving shaft 20. S aft 31 is geared to shaft in a one to one ratio for driving shaft 32 35 which serves to drive shaft 33 by means of driven clutch member ostation number,

clutch members 34 and 34'. These clutch members are brought into engagement by the tension of coil spring 34". Geared to shaft 33 in a lesser ratio than one to one is shaft which makes one revolution to as many revolutions of shaft 33 as there are signals constituting the number of the called station, bearing in mind that where it is desired to use both letters and numerical digits to complete a shift signal, and probably a space signal, may have to be trans mitts-d between the letters and. numerical digits. Shafts 3i and 32 are continuously rotating while motor 21 is operating. The 34', inn stopped sition, is, disengaged from the driving c utch member 34: by the clutch stop arm 35 which is controlled by magnet 33, the cperetion o1? which will be hereinafter described.

station code number.

In the particular arrangement illustrated in the drawing, three studs 32', 33 and 39 are shown in Fi s. l and 2, but as ststed shove, as many stn' s maybe provided no there are signals required to transmit the complete In a case where there are four digits in the station code number, four studs are provided, one for operating such of the four keys and the four keys must be operated during a single revolution of shaft 30 in order that the station code numassociated stud.

her can be transmitted to the distant or calling station. Each of key levers 13 may be equipped with a flat detachable member for providing a hearing plate for engaging its It was stated above that sha-ft 33 makes as many revolutions during one revolution of shaft 30 as there are signals in the called station number. This provision is necessary 55 inasmuch as shaft 33 which operates at the 69 code some speed as shaft 18, has to complete one revolution in order to transmit each combination of signal impulses and in the case where there are four digits or signals in the station number and consequently there are to be transmitted four combinations t of impulses, shaft 33 has to complete four revolu:

tionsinthe-interval in which it takes shaft 30 to complete one revolution. Therefore, by means of gear arrangements between shafts Therefore, as sha .30

in 1g. 2 because in t 33 and 3 0, shaft 30 is madeto rotate at a speed having a ratio of one to four with that of shaft 33.

Fig. 3 shows in schematic form only so much of the circuit at a subscribers station A as is necessaryto give a clear understanding of the operation of the apparatus shown in Figs. 1 and 2. T and R represent a portion of the subscribers loop circuitextending through the subscribers printer set 50 at station A to a central ofiice, (not shown). When a subscriber at a distant station desires a connection to the subscribers station shown in Fig. 3, the connection is established in the manner described in the Locke-Kinkead copending application, supra. Should, however, the subscribcrs printer set be unattended at the time the connection is requested and the distant subscriber still desires to have the connection established, the operator at the central ofice operates a key which momentarily opens the loop circuit to cause the releaseof e slow-release relay 51. The release of relay 51 closes an operating circuit for relay 36 which, in operating,'w1thdraws the clutch stop arm 35 from, engagement with the driven clutch member 34. Relay 36 in operating closes a locking circuit for itself from grounded battethrough the relay winding, to the normal y closed contact 52, to ground. This locking circuit ismaintained closed for approximately a complete revolutionoii maintnined in on 0 elated position or the duration oi the same interval.

The Withdrawal of clutch stop arm 35 per-- shaft 30 and consequently role 33 is Ice speed of shafts 32, 31 and 20. The rotation of shaft 33 drives shaft 30 at a speed having a ratio of say, for the purpose of illustration, one to three with that of. shaft 33, assuming that there are three digits in the code number of station A. Assuming that the shaft 30 is in a. position wherein stud 39 is about to on age its associated keg lever (not as shown at figure stud 39 is shown as having passed from engagement with its'key lever), the start of rotation of shaft 30 will cause stud 39 to depress its key lever and to thereby send out over the line the signal combination representin the first digit of the called station code num r. The continued rotation of shaft 30 causes the selector key' levers respectively associated with studs '38 and 37 and corresponding to the other digits of the called subscriber's code number to be momentarily de ressedj to their operated positions, in turn, w ereby the combinations of impulsesv controlled by said selected keys, are transmitted over the sending contacts 53 which are integral parts of bustion printer sets, characterized in this,

driving called subscribers station for selecting and' bars 22 and 23, to the loop circuit T-R. In the time that the three-signal combinations are being transmitted to the loop circuit, shafts 18, 20, 31, 32 and 33 are each completing one revolution to each signal combinav tion transmitted.v g

Immediately after the last stud 37 has operated its associated key lever an indent 54 in the left-hand end of shaft receives the movable spring of. contacts 52 to open the locking circuit for relay 36. .Relay 36 releases and thereby causes the clutch stop arm to drop back from the driven brush member actuating certain contacts in response to a signal received from the central oflice to transmit back to the printer set at the callin station certain signal combinations in a de nite sequence corrspondingto the characters constituting'the called subscribers stafor starting said motor,

tion number and other means included in said keyboard operating means for automatically efi'ectingthe disconnectionof said first mentioned means immediately'after the desired number ofsignal combinations have been transmitted. I I

2. A circuit of the type used in a printing telegraph exchange system for communication between printer sets, over a line, said printer sets each having a, keyboard characterized in this, that means are associated with the keyboard of the printer for engaging a up of key levers in a predetermined order or transmitting a code signal upon the application to the line. at a distant point of a special non-signaling'potential, said means antom'atically' disconnecting itself from' the keyboard after transmitting thecode combination once. I 3. An answer-back arrangementjor asubscribersprinter set comprising a motor, a relay responsive to-curren'ts of one polarity. a shaft associated with said'motor and adapted to be rotated upon the actuation of said motor, a driven member adapted to be driven by said shaft but normally disengaged therefrom, a mag net responsive to the operation of said relay for causing the engagement ofsa-id shaft with said driven member for one complete revolution of said member, a keyboard, key levers for said keyboard and means for depressing.

digits of a group of said key levers in a predetermined order upon rotation of said drlven member.

4. A telegraph exchange system, a central oilice, a subscribers station, a printer setat each of said stations, means ats'aid central oilice for establishing connections between printer sets at any two subscribers stations, driving mechanism for each of said sets, a driven mechanism in eng able relation with one of said driving mac anisms, a camming element controlled by said driven mechanism, a device responsive to a'signal from said central oflice for efiectin an en agement between said driven mechan am an said one driving mechanism whereby the actuation of said driven mechanism causes to be transmitted from one subscribers station to another a series of impulse comto the digits of the code number of one su ribers station, and means included in said driven mechanism for automatically driven mechanism and said device immediately after the last impulse combination of the subscribers station number is transmitted. I 5. A telegraph exchange system according to claim 1, wherein the driven mechanism comprises two rotatable members arranged t subscribers station, binations eorrespondm operate at different speeds.

6. A telegraph exchange system according to claim 4, whereinthe camming element is a rotatable shaft iii engageable relation with the keyboard of one (if said subscribers printer sets, and arranged to cause to-be transmitted from said keyboard one or more. signal combinations during one revolution of said Shaft.

7. A'telegraph exchange system according v to claim 4,-wherein the evice for engaging said driving and said driven mechanisms is.

an electromagnetic relay arranged to operate in response to the signal received from the central oflice and to remain operated until the termination of theinterval in which the combinations corresponding to the the subscribers station code are being transmitted.

8. A telegraph exchange system according to. claim 4, wherein the means effecting the signal a rotatable member 7 face in englageable relation with said device whereby t e engagement between said surface and saiddevice causes a nism. 9. In atelegraph systemcomprising a keyboardoperated sender, a line, and devices forim'pressmg upon 'theli-ne code combinations effecting the release of said release of said driven mechanism comprises having an indented sur- 0 t disengagement between said drlvlngand said drlven'mecha- I characteristic of the station wherein the sender is located, said devices comprising mechanisms for operating the keyboard sender, said devices being actuatableto operatethe key board in conformity to the definite code combination in response to the application to the line of a special non-code potential.

10. A system according to claim 9 provided with means at' a distant point for imposing the'special non-code potential upon the line.

11. A system according to claim 9 in which the line extends through a central ofiice to a connected subscriber and havingl a circuit changing device at the central 0 cc to connect a source of special non-code potential upon the line.

V In witness whereof, I hereunto subscribe my name this 11th day of December, 1931. CUTHBERT C. LANE. 

